As well-known in the art, how to define faults or errors is the first consideration to develop a fault processing model for a home network system. A conventional method defining faults finds problems to be resolved in related fields and defines the faults based on the problems.
To this end, a range of faults to be considered should be decided on the basis of the expert knowledge in related fields, and those faults should also be defined under a basis for specialist systems in the fields among several bases of doing so.
In a recent home network environment, there are a variety of heterogeneous fieldbus devices such as RS422, RS485, LonWorks, CAN, PROFIBUS and so on, as well as many types of devices from simple sensor devices to intelligent systems. Due to wired/wireless protocols/networks supported by those various devices, the home network environment has a more complicated network topology structure.
Such a home network environment has a high fault possibility owing to the complicated network topology structure. To deal with this, a lot of techniques have been proposed which detect and recover potential faults.
Meanwhile, according to a conventional technique for fault detection and recovery against faults in the network environment, a detection signal is provided from a watch-dog controller to a watch-dog generator at periods set by a processor. When a first time-out takes place, the watch-dog generator reports this to the watch-dog controller, which then provides the processor with a non-maskable interrupt (NMI) for execution of recovery operation.
However, when there occurs any hardware fault in a system hardware board with embedded processor or infinite loop status of software due to program errors, the conventional fault detection and recovery technique first generates NMI for recovery of the abnormal status of the processor without resetting the processor. Next, if the abnormal status of the processor is still not recovered, the conventional fault detection and recovery technique resets the system hardware board to escape from the abnormal status. In this manner, since the conventional technique simply takes into consideration the normal or abnormal status of the processor and the infinite loop status of software, it may be applied to a simple system but is not suitable for an integrated system based on ubiquitous environments such as a ship where various faults may occur.